ci: Remove unused "Add Wallet Framework Issues/PRs to Project Board" workflow (#7544)

## Explanation

This workflow is unused.

## References

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Are there other links that reviewers should consult to understand these
changes better?
Are there client or consumer pull requests to adopt any breaking
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* Fixes #12345
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## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Removes an unused GitHub Actions workflow that auto-added Wallet
Framework PRs/issues to the MetaMask project board.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
e031c52. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: Mrtenz